The present invention is related generally to wireless charging systems and, more particularly, to demodulating a frequency shift keying modulated input signal.
Frequency shift keying (FSK) is a technique for communicating data by discrete frequency changes of a signal. The simplest FSK scheme is binary FSK, in which the frequency varies between two frequencies to communicate binary data, but more than two frequencies can be used for the FSK modulation.
FSK is used in a great variety of applications such as for contactless key cards for controlling door locks, smart ID tags and smart labels that can be attached on books and other products offered for self-service sale, implanted devices like cochlear implants and other hearing aids, implanted programmable pacemakers, and control signals for wireless charging systems.
The power consumed by demodulation and the cost of the demodulator of the FSK signal are often major design factors, especially if the receiver and FSK demodulator are in a battery powered device.